UNITED NATIONS (Reuters) — A U.N. report
on how Syria's neediest civilians are often not accessible to
humanitarian relief workers makes it clear that the government of
President Bashar al-Assad shoulders most of the blame, a U.S. official
said on Tuesday.

A month after the 15-member U.N. Security Council achieved rare
consensus to approve a resolution demanding rapid, safe and
unhindered aid access in Syria, including across borders, U.N. chief
Ban Ki-moon said in a new report that the situation "remains
extremely challenging.

His report, which was delivered to council members on Sunday but has
not been officially released, criticized both the government and
rebels for hindering access to civilians caught in the crossfire of
the three-year civil war.

But in Washington's view, Ban's report was especially damning for
the government.

"What the report shows is that the magnitude and frequency of
violence committed by the Assad regime far outstrips that of the
armed groups in Syria," a U.S. official told Reuters on condition of
anonymity.

"The Syrian government's massive and indiscriminate use of violence
is the single most important factor driving the humanitarian
crisis," the official said. "The report is very clear on this and in
pointing to the government's failure to implement the resolution's
provisions."

Syria's U.N. ambassador, Bashar Ja'afari, rejected the "biased and
ungenuine (U.S.) way of looking at the report."

He told Reuters that Washington did not "acknowledge the huge
positive developments achieved between the Syrian government on one
hand and the OCHA (U.N. Office for the Coordination of Humanitarian
Affairs) on the other hand."

"The American approach has been negative from the beginning of the
crisis in Syria," he added.

"DEPLORABLE BEHAVIOR"

Ban's first report to the council on the implementation of the
February 22 resolution said 175,000 people remain besieged by
government forces and 45,000 people trapped by opposition groups. No
new ceasefires were brokered to gain access to these areas and there
were breaches of existing ceasefires.

Some 9.3 million people in Syria need humanitarian assistance, Ban
said, while another 2.6 million have fled the three-year civil war,
sparked in March 2011 by a revolt against Assad.

The Security Council is due to discuss Ban's report on Friday.
Several council diplomats told Reuters that it was highly unlikely
that Russia would agree to declare Assad's government in
non-compliance with the February 22 resolution, a move that could
trigger new calls for sanctions.

Russia, supported by China, has shielded its ally Syria on the
Security Council during the conflict. The two had previously vetoed
three resolutions that would have condemned Syria's government and
threatened it with possible sanctions.

The U.S. official rejected the idea that moderate opposition groups
should be equated with extremist groups fighting to topple Assad,
including al Qaeda splinter groups such as the Islamic State of Iraq
and the Levant, also known as ISIS, and the al-Nusra Front.

"Differentiating between groups like al-Nusra and ISIS, which have
blocked humanitarian access and committed atrocities against
civilians, and moderate civil and armed opposition groups that have
facilitated humanitarian access is very important," the official
said.

The U.S. official added that Syrian government forces continue to
drop barrel bombs, fire artillery and launch airstrikes against
civilian targets.

"We have seen that moderate opposition groups, frequently working
with relief organizations and local councils, have been instrumental
in facilitating the delivery of aid to desperate civilians,
including in Aleppo and Idlib," the official said.

"It is the Assad regime that has repeatedly used bureaucratic
obstacles, like visa applications and border controls, to block
passage of humanitarian assistance," the official said. "This is
deplorable behavior on the part of a member state."

U.N. aid chief Valerie Amos has repeatedly expressed frustration
that violence and red tape have slowed aid deliveries across Syria
to a trickle.